The 3G (3rd generation) packet data feature allows users to exchange packet data between a mobile station (MS) and an IP data network. A Packet Data Serving Node (PDSN) interfaces between data transmission in the packet data network and the data transmission to the MS via a Radio Access Network (RAN) and air interface. PPP (point to point protocol) is used to support the data link layer between the PDSN and MS. Therefore, a PPP session needs to be established before PDSN-MS, IP datagram exchange can begin.
For each packet data session, a “main” packet data service instance (PDSI) is required to negotiate and setup the PPP session and support Mobile IP (MIP) registration (if MIP is supported). A packet data session can support multiple packet data service instances (PDSIs—up to six can be supported per the 3GPP2 A.S0011-A.S0017-A (TIA-2001-C) standards specifications). Therefore, one of these PDSI's serves as the main PDSI and is used to support PPP negotiation and MIP registration for the packet data session. Any additional PDSIs supported by the packet data session are considered auxiliary service instances. Prior to establishment of any auxiliary PDSIs, however, a main PDSI must be setup and a PPP session first established.
PPP connection establishment procedures are required whenever a new packet data call is initiated, an inter-PDSN dormant reactivation occurs, an intor-PDSN active handoff occurs, or an inter-PDSN dormant mode handoff (DMHO) occurs. MIP Registration is also required when Mobile IP is supported. Resources such as air traffic channels, A8 and A10 bearer resources, and SCCP connections are usually required at least to complete PPP establishment and MIP registration. However, currently these resources may be held until the call is disconnected, until an MS or RAN inactivity timer expires, or until the PPP session timer expires. For situations such as dormant mode handoff, in particular, this can result in a relatively long period of time during which network resources are blocked from other revenue producing uses. Moreover, in PDSN border areas, or during peak traffic times when PDSNs are running near capacity, inter-PDSN dormant mode handoffs can occur frequently and thereby compound this problem.
Accordingly, it would be desirable to have a method and apparatus that improve the resource efficiency of inter-PDSN dormant mode handoffs.